I bought a secondary off ebay but added two more bodies on for a 4 way setup. It's very easy. If I had known about this source of the regulator bodies, I would have done it all from scratch
I went to Harbor Freight for the 1/4" ball valves and quick disconnect; Adventures in Homebrewing for the 1/4" NPT x 1/4" male flare adapters; Home depot for the pipe nipples, and two 1/4" to barb valves came with my original. I will keep one as a spare and am using one for the end of my regulator setup.
keeping a valve on the end will keep the system closed if I have to remove the CO2 tank. that three piece setup you see on the right is the incoming pieces from the CO2 tank.
From right to left:
1. male disconnect hooked up to 1/4" barb and that will come from the primary regulator
2. female disconnect will be sticking outside of my keezer collar
3. hose barb and 1/4" female coupling to be inside the keezer. The coupling will actually be inside the wood as it goes through
This setup is all flare because I wanted the ease and it really didn't cost much more (I'm dirt poor so if I can do it...). I'm not worried about check valves b/c I have in line check valves that will be a few inches from the gain-in disconnect on the keg. The disconnect on the outside makes it easier for maintenance for tank removal. plus i saw the disconnects and they were so cheap so I had to do it b/c it looked like a cool idea
Initial secondary off ebay: $50 (although if you start from scratch, less)
4 ball valves, 1/4" plug, male/female disconnect set: $19
2 additional bodies plus gauges: $36
2 extra pipe nipples, female hose barb, coupling: $10
Adapters: $12.30 including shipping
total cost (assuming I'm remembering everything): $127.30
If I had done the initial bodies from scratch it would be about $15 less.
that's $113 - $127
for something that costs $140 for taprite, $241 for micromatics, or $210 for the economy one from Beverage Factory. And those are without flares if you wanted them.
Just thought I'd share since it was fun to make and will be a sweet addition to my keezer.